Icelandic has a strict rule for its sentences: the conjugated verb is always the second element in a main clause. This is known as the "Verb-Second" or V2 rule.
If a sentence starts with a subject (like ég vinn...), the verb naturally falls into the second slot. But if you move a time or place word to the beginning of the sentence—which is very common—the subject and verb must swap places (invert) to keep the verb locked into position number two.
Time Phrases
Phrases like í dag (today) and á morgun (tomorrow) act as a single block of information. Because they take up the first slot, the verb immediately follows them, pushing the subject into the third slot.
Adverbs of Frequency
The V2 rule applies to single-word adverbs as well. Words like venjulega (usually) and stundum (sometimes) are often placed at the start of a sentence. Notice how the subjects (hún and læknirinn) come immediately after the verbs (vaknar and kemur).
Sequence Words
When describing the order of events, you will often start sentences with sequence words like núna (now), seinna (later), svo (then), or strax (right away). Placing these words at the beginning triggers subject-verb inversion.
Flexible Word Order
Moving an adverb to the front of the sentence is optional, but it changes the emphasis. If a sentence has multiple time elements, only the one at the very front triggers the V2 rule. In the following example, í dag takes the first slot, the verb borðum stays in the second slot, and strax sits safely at the end.
